1. Field of the Invention
The present invention relates in general to a plasma display panel (PDP). In particular, the present invention relates to a rear plate of a PDP and the method for forming ribs thereon.
2. Description of the Related Art
Recently, a variety of flat panel displays, such as a liquid crystal display (LCD) and a plasma display panel (PDP) have been intensively developed to replace cathode ray tube (CRT) displays. In PDP technololgy, an ultraviolet light is emitted to excite the RBG phosphors to produce visible lights. The advantages of the PDP include a large display area, wide viewing angle, and intense brightness.
The PDP has a front plate and a rear plate spaced apart to each other with the peripheries thereof sealed. In general, the PDP includes barrier ribs for partitioning the discharge spaces. The barrier ribs prevent discharge coupling and color cross-talk between adjacent cells. The traditional method for forming the ribs is described hereafter with FIGS. 1A and 1B.
As shown in FIG. 1A, the address electrodes 12 are formed on the glass substrate 10. The dielectric layer 14 is formed to protect the address electrodes 12 after sintering. The rib material layer 16 is formed on the dielectric layer 14. The dry film is laminated on the rib material layer 16. After exposing and developing, the dry film 18 is patterned as shown in FIG. 1A.
Referring to 1B, the rib material layer 16 is patterned by sandblasting to form the ribs 16a. 
In the above-mentioned traditional processes, the dielectric layer 14 under the ribs 16a is used to protect the address electrodes 12 from damage in the sandblasting step. A sintering step is needed after forming the dielectric layer 14, the manufacturing time is longer and the manufacturing cost is increased. Moreover, the height of the ribs 16a is about 100xcx9c200 xcexcm, therefore the sandblasting time is too long to keep the uniformity of the bottom width and the profiles of the ribs 16a. If the lateral action between the sands and the rib material is strong in the sandblasting step, the bottom area of the ribs 16a will be small. The size of the ribs 16a affects the size of the discharging cell and the strength of the ribs 16a. If the width of the ribs 16a is narrowed, the space of the discharging cell is increased so that the coating yield of the phosphors is enhanced. Therefore, the brightness is enhanced and the consumption of power is reduced. When the width the ribs 16a is too smaller, the strength of the ribs 16a is also reduced. The height of the ribs 16a is very high now, if the width of the ribs 16a is further reduced or the height is further increased, the stability of the ribs 16a is damaged and these ribs 16a may collapse.
The present invention provides a method for fabricating ribs of a PDP. In this method, one sintering step can be eliminated, the width of the rib and the profile of the ribs can all be effectively controlled, and the space of the discharging cell can be increased without damaging the stability of the rib.
The present invention provides a method for forming PDP ribs. First, a plurality of address electrodes and base plates are formed on the glass substrate. The address electrodes and the base plates alternate with each other, and a predetermined distance is formed between each address electrode and each base plate. A rib material layer is formed above the address electrodes, the base plates and the glass substrate. A patterned mask layer is formed on the rib material layer. The rib material layer is sandblasted to form a plurality of ribs accord to the pattern of the base plates. The shape of the base plates can be changed on demand so the structure of the ribs can be changed. Alternatively, a passivative film can be formed on the address electrodes to prevent from damage in the sandblasting step.
The present invention also provides a rear plate of the plasma display panel (PDP). The rear plate includes a glass substrate, a plurality of address electrodes, a plurality of base plates, and a plurality of ribs. The address electrodes and the base plates alternate with each other and are parallel to each other. There is a predetermined distance between each address electrode and each base plate. The ribs are disposed on the base plates, and the bottom width of each rib is the same as that of each base plate.